title: The effects of intra-arterial vasodilators on radial artery size and spasm: implications for contemporary use of trans-radial access for coronary angiography and percutaneous coronary intervention.
abstract: BACKGROUND
  Transradial access (TRA) offers advantages including decreased vascular complications, reduced length of hospital stay, and reduced cost. The size of the radial artery (RA) limits the equipment that can be used via TRA. Intra-arterial (IA) vasodilators prevent and treat RA spasm, yet are not uniformly used in TRA and their effect on the absolute size of the RA remains unknown.
  
  
  METHODS
  121 patients undergoing TRA for cardiac catheterization were included. 78 patients underwent RA angiography prior to administration of IA vasodilators ('no vasodilator' group), 43 patients underwent radial angiography after administration of an IA verapamil and nitroglycerin cocktail ('vasodilator' group). Quantitative angiography was used to compare the RA diameters.
  
  
  RESULTS
  Clinical characteristics were similar between the groups, except that patients in the 'no vasodilator' cohort were taller (1.67 ± 0.1 m vs. 1.73 ± 0.1 m, p=0.002), and heavier (84.9 ± 18.2 kg vs. 75 ± 17.1 kg, p=0.003). In the 'vasodilator' group the proximal RA diameter was larger (2.29 ± 0.47 mm vs. 2.09 ± 0.41 mm, p=0.02) as was the narrowest segment (1.83 ± 0.56 mm vs 1.39 ± 0.43, p<0.0001) compared to the 'no vasodilator' group. At the RA origin, 79.4% of those in the 'vasodilator' group were larger than a 6 Fr guide catheter, compared to 51.4% in the 'no vasodilator' group (p=0.004). At the narrowest segment a higher percentage of RAs in the 'vasodilator' group were larger than a 5 Fr guide catheter (65.1% vs 26.9%, p<0.001) and a 6 Fr catheter (34.9% vs 10.3%, p=0.001).
  
  
  CONCLUSIONS
  IA vasodilators increase pre-procedural RA diameter in patients undergoing cardiac catheterization via TRA. This increase in diameter has important implications for procedural planning.
  Boyer et al. performed a blinded controlled clinical trial investigating the effects of intra-arterial vasodilators on radial artery size and spasm during cardiac catheterization. The study demonstrates that intra-arterial vasodilators significantly increased the radial artery size throughout the entire course of the vessel and significantly decreased the amount of radial artery spasm. The authors conclude that these findings support the use of intra-arterial vasodilators during cardiac catheterization and have important implications for emerging technologies such as larger bore sheathless radial procedures.
authors.affiliation: Division of Cardiology, University of California, San Francisco, CA 94143. Electronic address: nathan.boyer@ucsf.edu.
authors.forename: Nathan
authors.initials: N
authors.lastname: Boyer
authors.forename: Anna
authors.initials: A
authors.lastname: Beyer
authors.forename: Vipul
authors.initials: V
authors.lastname: Gupta
authors.forename: Hossein
authors.initials: H
authors.lastname: Dehghani
authors.forename: Vindhya
authors.initials: V
authors.lastname: Hindnavis
authors.forename: Kendrick
authors.initials: K
authors.lastname: Shunk
authors.forename: Jeffery
authors.initials: J
authors.lastname: Zimmet
authors.forename: Yerem
authors.initials: Y
authors.lastname: Yeghiazarians
authors.forename: Thomas
authors.initials: T
authors.lastname: Ports
authors.forename: Andrew
authors.initials: A
authors.lastname: Boyle
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017023:Coronary Angiography / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D062645:Percutaneous Coronary Intervention / Q000379:methods; D017534:Radial Artery / Q000187:drug effects* / Q000473:pathology; D013035:Spasm / Q000517:prevention & control*; D016896:Treatment Outcome; D014665:Vasodilator Agents / Q000627:therapeutic use*
chemical_list: D014665:Vasodilator Agents
keywords: Cardiac Catheterization; Radial Artery; Transradial; Vasodilation